Curved Bridges

[Anonymous]

I'm having some problems finding a half decent curved 18"r bridges. I can find plenty of straight but not much in curves. Has anyone but a scratch curved bridge out of plastic or wood?

Thanks,
Dave

[thirdrail1]

Dave, there's a good reason you can't find curved bridges. They don't exist in real life! The span section of every bridge is straight, whether it is a girder span or a truss span. Bridges may appear "curved", especially trestles, but they are straight between pilings or piers. Where the prototype had a curve on a bridge, they widened the straight bridge to accomodate the curved track on it.

[Anonymous]

Ouch that hurts. The plan I picked up out of 101 Track Plans has one big pile of bridges on curves.

I guess I should look at a double width straight bridge to handle it. Not sure what you think of that.

Dave

[thirdrail1]

That's exactly how the prototype would do it. You mention a plan from 101 Track Plans. Are you sure the bridges aren't trestles? With a distance between bents of 16 to 20 feet, such a bridge would appear curved. Trestles are easy to scratchbuild once you understand how they are built. Many modelers love high, curved, trestle bridges, although the prototype railroads hated them for the maintenance involved.

[Anonymous]

I noticed a listing on eBay for a number of bridges in HO and a good number of them were curved wooden tresles. I think it's still active. got to the HO section and search for "bridges". One thing I do, when I find something interesting photo wise on the web I right mouse button click on it and do a "save picture as" function. I'm building a whole library of photos of the period I want to model. Do the same when ever you come across a good bridge picture.....Walt

[Anonymous]

Dave,

I design highway bridges for a living. I also have the 101 track plans book. If you tell me which one you are interested in building, I will let you know what I recommend for the bridges.

Off the cuff, I think you should consider building a viaduct of short deck girder spans like the 30 ft bridge produced by Micro Engineering. However, if you need clearance under the bridge (for another track for example) you should probably use a thru girder bridge like the 50 ft span produced by the same manufacturer. Walthers also produces a wooden trestle model which may be more appropriate with your era or locale. Anyway, if you give me the plan number, I'll see what you're up against.

Ed

[Anonymous]

Thanks for the info. I'm currently thinking about number 29 Nantahala & Smoky Mtn Gorge RR. It looks like more of a challenge than my first flat RR attempt. It appears to have number of tressle bridges. As well as a covered bridge. Any assistance is appreciated.

Dave

[Anonymous]

I saw that ebay auction and wow did he have some nice tressles. I was impressed by the quality of his stuff.

Dave

[Anonymous]

Yes, I too liked what I saw. Only a lack of an ongoing layout kept me from bidding. He had all kinds, large curved tressles, metal, etc. His note that these were leftovers from his layout also was impressive. I should have such leftovers. It's gone already but does anyone know for how much?....Walt

[Anonymous]

Look closly at curved bridges ( not trestles) on a real railroad. They are actually straight bridge sections set at angles to each other. I've make several curved steel bridges out of "el cheapo" Atlas bridge parts simply by cutting the ends at angles to each other and gluing them together. It takes a little "fiddling" but it works out great. Be sure that you reinforce the joint.

[Anonymous]

Walt, I checked the closed auctions out and it closed at 194.44. A little steep for my blood but he was selling good equipment.

Dave

[Anonymous]

Excellent idea. I think I'm going to give it a try.

Dave

[Anonymous]

Dave,

Plan Number 29 appears to be an ambitious plan from my point of view. In addition to the many bridges, the ruling grade is 4%. But I digress …

Starting at Piedmont headed to Paint Springs you cross a double track bridge over a waterway. The plan appears to call for a twelve-inch span. I recommend the Walthers Double track truss bridge, which is about eighteen inches long. I have heard that this bridge doesn’t have the necessary clearance to run double stack cars but I doubt you will be running this length car on 18 inch radius curves. You would have to take the curve out of this portion of the track plan to install an eighteen inch span. Another option is to use the double track thru girder bridge made by Central Valley, which spans 72 scale feet. The second bridge occurs just before the tunnel after passing Paint Springs. You could use a fifty foot deck girder bridge by Micro Engineering because there is plenty of overhead clearance over the track below; however, it probably would not look as good as a thru girder bridge because an eighteen inch radius curve on this span would look a bit like a caricature. The next bridge, after the tunnel, may be handled the same way since there is no problem with clearance under the bridge.

Then you come to a three span bridge. You will probably have to scratch build or kit bash a model for the first span. The first span crosses over another track at a severe skew but there is a good bit of clearance over the track below. The easy solution for this span is to kit bash a Micro Engineering 50 foot plate girder span and build it on a suitable skew. Again, I believe this bridge will look better as a thru girder but building a thru girder bridge on a skew is a bigger challenge. The second and third spans would also look good as plate girder spans of either the deck or thru girder type. It would be highly unusual to see a truss span mixed with plate girder spans of the same length.

After the three span bridge before Gorge Crossing you go a good ways before you get to the next span over the lower narrows. This bridge is not very high over the track below, so a through span is needed. You could use a through truss but you will probably have to kit bask or scratch build one for this to have adequate horizontal clearance due to the tight curve. A fifty to sixty five foot span should be fine here, but fifty works better than sixty five because of the curvature. The next bridge comes up just before Gorge Crossing over the Saluda River. Any straight bridge should do here but I would see if the 150 foot single track truss bridge made by Central Valley would fit into the length of the tangent track leading to the crossing. If you can’t fit the 150 foot bridge in here, another bridge matching one of the bridges already used would do fine. The reason you want to do this is because railroads have a ‘Family’ look, meaning that similar items are all built using the same techniques to save time and money.

The last bridge, the covered bridge on the branch line will probably have to be scratch built because I don’t know of anyone producing a covered railroad bridge. I believe Walthers recently released a covered roadway bridge but I don’t think it would work as a railroad bridge. If you are interested in wooden trestles, you could build the two bridges near Tallulah this way. It is really a matter of taste, so you should decide that for yourself. If you do, however, I recommend building the trestle with a main span deck truss in the middle for additional clearance and better appearance. As I recall, there is a picture of such a model trestle in Bruce Chub’s book, “How to Operate Your Model Railroad” and I recommend the book highly. I also recommend the book from Kalmbach(sp?) about Model Railroad Bridges and Trestles. Also, I recommend the special ‘Bridge Track’ manufactured by Micro Engineering which is supplied with the Micro Engineering kits and may be purchased in 36 inch flex track pieces.

Good Luck and let us know how it goes. - Ed

[Anonymous]

Dave, Wow, it must have happened in the last few minues. I think it was around $30 when I last looked at it and had about 2 days to go. I've just about gone my limit on eBay. The wife is starting to get the credit card bills! (chuckle) Some stuff goes cheap and some more than retail, you really need to know your prices going in....Walt

[Anonymous]

Dave

Just to add to Ed's last posting Campbell Scale Models do a craftman kit for a covered railroad bridge: they are distributed by Walthers and occasionally advertise in MR - as far as I know they don't have a website.

James

[Anonymous]

Ed, I thank you very much for taking all of this time to check this out for me. I will be looking at the info you have provided very closely.

I will keep you posted on the progress,

Dave

[Anonymous]

DAVE:OUR 58 BY 34 FOOT LAYOUT WILL HAVE BOTH CURVED TRESTLE AND WOODEN BRIDGE,WHEN IT IS SET UP FOR PUYALLUP FAIR(PUYALLUP WASH.)IN SEPT OF THIS YEAR,THE TWO GUYS THAT BUILT THE TRESTLE,DONT HAVE COMPUTERS,THE MAN THAT BUILT THE BRIDGE HAS EMAIL WILL SEND IT LATER

[Anonymous]

DAVE:CONTACT ME AT "[e-mail]"will pass along freinds email<,also click onto "TRACKSIDETRAINS.NET" to view our large o scale layout,click on layout/photo's "HUB"